Cutting device and tool therefor



Nov. 11, 1930. E. J. BEATTIE 1,731,564

' I CUTTING DEVICE AND TOOL THEREFOR Filed April 8, 1929 Patented Nov. 11, 1930 PAT NT OFFICE;

ERNEST J. BEATTIE, OF FALL RIVER, MASSACHUSETTS CUTTING "DEVICEFQAND TOOL THEREFOR Application filed AprilS,

- This invention aims to provide an rimproved cutting device, more specially designed for cutting plaster casts employed in v surgery andthe like, to convenience the re moval of the same, and a device also well adapted for trepanning and for removing sections of bone or bony structure. Myinventionwillbest be understood from a description of an illustrative embodiment thereof shownin the accompanying drawing, together with certain modifications in respect to details.

Referring to the drawing -Fig. 1, partially broken away and partially in section, illustrates one embodiment of my invention;

Fig. 2;is an enlarged detail, partially in section, ShOWiHgtllG lower portion of Fig. 1; Fig. 3 is a right hand elevation of the lower portion of Fig.1; 1 I a I Fig. 4 is a horizontal section on the line 4-4, Fig. 1, looking downward, 3 r Fig. 5 is an enlarged detail showing the lower end of thepre'ferred form 'of cutting toolg- V. Fig. 6is a cross section on the line 6 6, Fig. 5, looking downward; and Y Fig. 7 is adetail, partially insection, to

be referred to.

In a co-pendingapplication,-Serial No.

320,376, I have showna device adapted for somewhat similar uses with the present, wherein the cutting tool is carried by a port able 'motor, which latter is mountedinor provided with a suitable handle, bywhich the'motorandcutting tool may be moved about to permit the tool to be: employed in desiredmanner, the devicebeing connected by a flexible-conductor with asuitable source ofelectric current.

In many-instances, however, a device employing a portable electric motor with the cutting device or tool directly connected with it, is found to be undesirably heavy, and I have therefore in'my'present'invention shown a stationary motor 31, mounted upon a conveni ent stand or upon the wall, the shaft ofv the'motor being connected by a flexible shaft 32 of desired construction and length, with a relatively small and light portable tool 45 on the portable casing 35. The boss 45 has sired positi'onupon said boss. a

1929. serial No. 353,322;

carrying head 33. This head, as shown, coni .tains a drive shaft 34 to which the free end of the flexible 'shaft32 is suitably connected, and'upon this drive shaft, within the casing 35,is mounted a spirally toothed wheel 36, 5 Fig. 1. This wheel meshes with a spirally. toothed driving pinion 37 mounted upon a short upright shaft 38, journaled at its ends in suitable bearings therefor in the casting 35, the ratio of the gear and pinion'being such that the pinion shaft 38 may be driven at very high speed. I have found from 8,000 to 10,000 revolutions per minute to produce excellent results. The-casing 35 and its enclosed parts may conveniently be made so light as to be easily and delicately handled by the surgeon for anydesired purpose.

' The depending extended end of the inion shaft 38 is transversely grooved at 39, ig. 1, to constitute one member of a conventional clutch,the"other member of which is providedwith a corresponding transverse rib or fin 40 on the end of the tool carrying shaft 41. T his shaft is mounted in two combined radial and thrust ball bearings 42, 43, shown in dotted lines, Fig. 1. The bottom bearing 43 is shown in enlarged section in Fig. 2. These bearings are closely fitted within a housing cap 44 mounted to turn upon a depending boss v 7 so a circumferential groove 1nto which pro ects the innerend of aretaining and clamping screw 46, see Fig. 1, which latter, by traveling .frc'clyf'around in the groove permits free rotation ofthe housing cap upon and with respect as tothe portable casing 35, yet retains the cap in its position upon said boss. The clamping screw also furnishes convenient means for clamping the cap against rotation in any dew- 1 The ball bearings 42' and 43 are retaine'd in suitable spaced relation in the cap by a spacing sleeve 47, Fig; 2. v

The too'lficarrying shaft 41, see Fig. 2, near its lower end is provided with a shoulder 48, to seat'upon the inner cone'of the lowermost ball bearing 43,to preventthe draft of the toolifrom tending to draw'the carrying shaft outward from itsbearings.

Theftool itself, marked 14 in'F igs.-1 to '6inelusive, may be held in position by a suitable conical and threaded end, or it may be made integral with the short drive shaft ll, as here shown.

The cutting tool, in whichever type of de vice employed, is preferably of novel construction, shown more in detail in Figs. 5 and 6. Referring to these figures, it wiil be observed that the lands 4L9 are of relatively high pitch and preferably such as to extend spirally at an angle of fortyfive degrees or thereabout with the axis of the tool. As shown in .Fig. 5, four spiral lands are employed, two

of which merge at their lower ends into the drill-like end cutting edges 50, the intervening lands terminating at 51 short of and having no connection with any drill-like cutting V edges; The drill-like cutting edges 50 are dialnetrically opposite each other'and ofcomanonbevel and formation, the construction of the tool being such that whenforced endwise into the body which is to be. cut, the tool will, by, its cutting edgesl50,.'drill its way into or through the samelike an ordinary drill, the intervening short lands then performing no, effective action, unless possibly to assist in freeing the hole ofchips produced by the drilling operation. The endwise or drilling movement having been. completed, the tool maythereafter be operated sidewise through th'ebody to be cut, whereupon'all four of the lands, those merging into the drill-like end cutting edges, as well as the intervening ones, become effectlve to promote rapid lat eral cutting and self-clearing action.

'Referrin g to Fig. 6 which, as stated, is a cross-section of the tool shown in Fig.5, it will be noticed that the flutes 52 are deep and that the rear bounding walls 53, thereof are and preferably will be slightly concave, to

facilitate the lateral cutting action of the tool which, so far as known to me, is availed of for the first time in the tool disclosed in my invention. The extreme outer ends of the lands are beveled oil", as at 54, to, assist in providing satisfactory lateral cutting-edges 55, and to provide proper clearance to reduce friction during the cutting operation.

In my novel side-cutting spirally-toothed tool, as illustrated in Figs. 5 and 6, a left hand spiral is employed and the cutting edges 55. face to the left. In other words, if the spiral is left-hand, the cutting edges are also leftprovided with spiral cutting edges that are of the opposite hand to the spirals, that is to say, if the cutting edges are right-hand, they are ordinarily upon left-hand spirals, and vice versa. So far as I know, my invention provides for the first time in the art spiral side-cutting edges that are of the same hand as the spirals, that is to say, left-hand cutting edges for, left-hand spirals, or right-hand cutting edges for right-hand spirals.

Referring again to Fig.1, I have provided means for introducing a cooling fluid to the interior of the housing cap 41, for the purpose of preventing, to a suiiicient degree, overheating of the tool when employed in trepanning or other heavy operations, In the present instance, have provided a flexible tubefifi, which is attached to the housing at one end and to a suitable supply of cooling fluid, such, for example, as methyl chloride, conveniently at hand, and which, while not interfering appreciably with the free movement or portability of the toolcarrying head, will at all times conduct thereto a suflicient supply of the fluid to prevent over-heating of the toolv or the parts in which it is mounted. To permit circulation of this fluid, the housing cap is provided with an exit opening 57, and the spacing sleeve within the cap is provided with one or more openings 58 to register with the outlet opening 57, to permit escapeof so much of the cooling fluid as it may be necessary to providean exit for. For coi-ivenience in handling, the cooling fluid above referred to is introduced as a liquid and flows in comparatively small quantities, but

expands and gassifies within the cap and escapes as a gas. 7 g Referring now to Fi e. 1 and 4,1 have provided upon the side of the housing cap 44; a vertical groove to receive a corresponding rib upon the inner faceof the vertically adjustable support 59, carrying at its lower end the swinging guide 60 pivoted to the support at 61. This, guide may bev of desired outline and area, and is provided with a reentrant slot 62 see Fig. 2, through which the cutting tool 14 extends. Beyond the pivot, 61 the guide is provided with an angularly extended clamping arm 63 screw-threaded at its free end and provided with a clamping nut (54-. The threaded end, of the clamping arm errtendsthrough a slot in the clamping segment 65, whichfprojects. outwardly from the lower end of the adjustable support 59 to furnish means in cooperation Withthe clamping nut for elampingthe arm 63and its attached guideplate 60 in desired'angular position to 'facilitatev'use of the cutting tool 14 at the desiredangle in its action upon the body that is to be'cut. r V r "The support 59 is vertically adjustable in the groove provided therefor in the housing cap, and is clamped inits groove by suitable.

means, conveniently clamping screws 66,

.tll)

i-' strut 29 following it.

Fig. 3. Vertical adjustment of this support upon the housing cap. provides for varying the possible depth' of drilling and cutting action ofthe drill in connection with the provision of desired angular cut by swinging the guide plate as described;

The device, fitted as in Fig. 6, may conveniently be used for removing sections or strips of bone in surgery. 1 i

In trepanning it is important that the end of the cutting tool be not pushed inward too far to rupture the dura mater, commonly obliquely upon and at the bottom of the strut 29, so that when the guide foot with its associated strut and cutter are. inserted through the hole in the skull 30, drilled there for in customary manner by suitable instruments well known in the surgical art and drilled obliquely as indicated, the guide foot may be inserted obliquely through this oblique hole until said foot presses, as it may, slightly upon the dura, whereupon the tool is then advanced sidewise, that is to say,

in a direction away from the point of View in Fig. 7, to cause the cutter 14 to cut an oblique kerf in and along the skull bone, the

As the motor is advanced, the surgeon holds the guide foot 28 closely. against the under side ofthe skull, so that the said guide foot will pass between the skull and the dura and, by lifting the dew. vice in this position, instead of in a sense pressing downwardupon it, functions by a pulling up operation, against the under side o1 the body that is being cut, rather than pressing down upon the underlying support which is beneath the body being cut, as would be the case where the guide 60 were used. Both the guide foot and guide may be used at the sametime, if desired, as shown in Fig. 7.

The broad area and the rounded. and beveled edges of the guide foot 28, Fig. 7 are I such that if the surgeon in manipulating it should momentarily fail to lift it into contact with the under side of the skull, it might be pressed lightly upon the dura without harm to the patient.

This device, Fig. 7 may be used to remove any given section of a skull for trepanning and doit with'the removal of less bony structure, and therefore I with .a more accurate subsequent fit, than by the instruments commonly used, whichremove a wider kerfor larger skull in the process. r

The cutting tool used, as in Fig. 7, will, of course, be very much smaller than that amount of the ordinarily used for removal of bone, plaster or the like. I would not for this purpose, Fig. 7, ordinarily employ a cutting tool larger than one-sixteenth of an inch in diameter, although, ofcourse, this diameter might be varied in any given instance.

For the removal of plaster casts, the guide foot would usually stand square with refer-' ence to the axis of the cutting tool, instead of oblique, as shownin Fig. 7, and if a rest at the upper side of the article being out were to be employed, that also would ordinarily stand square'with the tool, rather than oblique as shown in Fig. 1. 1

The cutting tool shown isv highly efiicient, whatever form of carrying device and drive may be provided, whether the motor be made portable, carrying the tool directly engaged with it, or whether the motor bestationary,

as here shown, and the tool carried by a port- 7 I able head flexibly or otherwise 'portably driven from the motor.

- My invention is not limited lar embodiments shown.

Claims:

1. A portable plaster cast cutting device comprising a carrier; a guide foot carried thereby; a tool holder mou nted in said car rier; a remote source of power; a driving connection between the latter and said carrier, constructed to permit'free movement of the latter relative to the former; and a sidecutting, spiral-toothed cutting tool' mounted on and to. be rotated bysaidtool holder.

2. A portable plaster castcutting device comprisin a carrier; a guide foot carried thereby; a tool holder im'ounted in said carrier; a remote source otpower; a. driving connectionibetween the latter andflsaid car-- rier, constructed to permit free movement of the latter relative to the former; and a side cutting tool mounted on and to be rotated by said tool holder. l v

portable plaster cast cutting device to the particucomprisinga carrier; a tool holder mounted thereon; a flexible driving shaft for said tool holder mounted on said carrier and to rotate said tool holde'r; and a side-cutting tool "holder; and means to supply-a cooling medium to'said toolholder or the tool mounted' tl ereon.- i f 5; A portable plaster cast cutting device comprising carrier; a tool holder mounted thereon; a side-cutting tool mounted on and to be rotated in said tool holder; and aguide plate angularly positionedupon said carrier and angularly positioned relative to the axis of saidtool.

ithereon; a side-cutting tool mounted on and I 6. A portable plaster cast cutting device comprising a carrier; a tool holder mounted thereon; a side-cutting tool mounted on and to be: rotatedin said tool holder; a guide plate upon said carrier and angularly adjustable relative to the axis .of said tool; and means to hold said guide plate in desired angular position.

7. A portable plaster cast cutting device comprising acarrier; atool holder mounted to be rotated in said tool holder; flexible means for driving said tool holder; a strut depending from said tool holder; and a guide platemou-nted on said strut.

8. A portablev plaster cast cutting device comprising carrier; a tool holder mounted thereon; a side-cutting tool mounted on and to be rotated in said tool holder; flexible means for driving; said tool holder; a strut depending from said tool holder; and a guide plate mounted on said strut and in angular position relative to the axis of said tool.

9. A portable plaster cast cutting device comprising a carrier; a tool holder mounted in ball bearings thereon; means to operate said tool holder; and a side-cutting spiraltoothed cutting tool mounted in andto be rotated by saidtool holder.

10. A portable plaster cast cutting device comprising acarrier; a tool holder mounted thereon; means to rotate said tool holder; a side-cutting spiral-toothed cutting tool mounted in and to be rotated by said tool holder; and a guide plate for and adjustable longitudinally in the direction of the axis of said cutting tool and holder.

11.1 As a new varticle of'manufacture, asmall high speed side-cutting spiraltoothed cutting tool for surgery, wherein the spiral cutting edges and spiral grooves are of the same hand or facein the same direction.

12. As a new article of manufacture, a small high speed side-cutting spiral-toothed cutting toolfor surgery, said tool provided also with drill-like end cutting edges.

13. As a new article of manufacture, a small high speed side-cutting spiral-toothed cutting tool for surgery, said tool provided witha pluralityofspiral side-cutting edges and with drill-like end cutting edges fewer in number than thespiral side-cutting faces.

14. As a new article of manufacture, a

surgeons small high speed side-cutting spiral-toothed cutting tool wherein the'spiral same hand or face inthe same direction, and

' wherein the following faces of the spiral grooves are under cut.

15. Asa new article of manufacture, a-

witha plurality of spiral side-cutting edges,

and drill-like end cutting edgesfewer in numher than the spiral side-cutting edges, one

ERNEST-J. BEATTIE.

speed side-cutting 1 I CERTIFICATE OF CORRECTION.

Patent No. 1, 781, 564. Granted November 11, 1930, to

ERNEST J. BEATTIE,

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, line 128, claim 5, strike out the word "angularly"; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 9th day of December, A. D. 1930.

M. J. Moore,

(Seal) Acting Commissioner of Patents. 

